For example, a personal computer (hereinafter, referred to as a “PC”) internally has a circuit board on which a heat-producing electronic component such as a CPU is mounted, and a heat sink unit abutted on the heat-producing electronic component for cooling the heat generated from the heat-producing electronic components is also mounted on the heat sink unit. In some heat sink units, elasticity against the heat-producing electronic component is added to alleviate a difference of heights of the heat-producing electronic components and provide sufficient an abutting force against the heat-producing electronic component.
Japanese Laid-open Patent Publication No. 10-223816 discloses a structure having an attachment clamp for mounting the heat sink on the circuit board and a spring interposed between the heat sink and the attachment clamp to apply elasticity between the heat sink and the heat-producing electronic component. However, in this structure, an attachment component or a spring is separately prepared in addition to the heat sink unit, and thus, errors maybe frequently generated in an assembling process.
Also, Japanese Laid-open Patent Publication No. 10-70383 discloses a structure which applies elasticity between the heat sink and the heat-producing electronic component by inserting a coil spring between the screw head and the heat sink during a process of fixing the heat sink to the circuit board by screws.
However, even in this structure, the heat sink unit fails to have a structure for applying elasticity on its own. Since the coil spring is installed when the heat sink unit is attached to the circuit board, errors may frequently occur.